Fluid inkjet systems typically include one or more printheads having a plurality of inkjets from which drops of fluid are ejected towards a recording medium. The inkjets of a printhead receive ink from an ink supply chamber or manifold in the printhead which, in turn, receives ink from a source, such as a melted ink reservoir or an ink cartridge. Each inkjet includes a channel having one end in fluid communication with the ink supply manifold. The other end of the ink channel has an orifice or nozzle for ejecting drops of ink. The nozzles of the inkjets may be formed in an aperture or nozzle plate that has openings corresponding to the nozzles of the inkjets.
During operation, drop ejecting signals activate actuators in the inkjets to expel drops of fluid from the inkjet nozzles onto a recording medium. By selectively activating the actuators of the inkjets to eject drops as the recording medium and/or printhead assembly are moved relative to one another, the deposited drops can be precisely patterned to form particular text and graphic images on the recording medium. An example of a full width array printhead is described in U.S. Patent Application Publication No. 2009/0046125, which is hereby incorporated by reference herein in its entirety. An example of an ultra-violet curable gel ink that can be jetted in such a printhead is described in U.S. Patent Application Publication No. 2007/0123606, which is hereby incorporated by reference herein in its entirety. An example of a solid ink that can be jetted in such a printhead is the Xerox Color Qube™ cyan solid ink available from Xerox Corporation. U.S. Pat. No. 5,867,189, which is hereby incorporated by reference herein in its entirety, describes an inkjet print head including an ink ejecting component which incorporates an electropolished ink-contacting or orifice surface on the outlet side of the printhead.
One difficulty encountered with fluid inkjet systems is wetting, drooling, or flooding of inks onto the printhead front face. This contamination of the printhead front face can cause or contribute to blocking of the inkjet nozzles and channels, which alone or in combination with the wetted, contaminated front face, can cause or contribute to non-firing or missing drops, undersized or otherwise wrong-sized drops, satellites, or misdirected drops on the recording medium and thus result in degraded print quality. Current printhead front face coatings are typically sputtered fluoropolymer coatings, such as those from PTFE and PFA. When the printhead is tilted, a UV gel ink at a temperature of about 75° C. (75° C. being a typical jetting temperature for UV gel ink) and a solid ink at a temperature of about 105° C. (105° C. being a typical jetting temperature for solid ink) do not readily slide on the printhead front face surface. Rather, these inks flow along the printhead front face and leave an ink film or residue on the printhead that may interfere with jetting. Thus, the front faces of UV and solid ink printheads are prone to be contaminated by UV and solid inks. In some cases, the contaminated printhead can be refreshed or cleaned with a maintenance unit. However, this approach introduces system complexity, hardware cost, and sometimes reliability issues.
There remains a need for materials and methods for preparing devices having superoleophobic characteristics alone or in combination with superhydrophobic characteristics. Further, while currently available coatings for inkjet printhead front faces are suitable for their intended purposes, a need remains for an improved printhead front face design that reduces or eliminates wetting, drooling, flooding, and/or contamination of UV or solid ink over the printhead front face. There also remains a need for an improved printhead front face design that is ink phobic, that is, oleophobic, and robust to withstand maintenance procedures such as wiping of the printhead front face. There further remains a need for an improved printhead that is easily cleaned or that is self-cleaning, thereby eliminating hardware complexity, such as the need for a maintenance unit, reducing run cost, and improving system reliability.
The appropriate components and process aspects of each of the foregoing U.S. Patents and Patent Application Publications may be selected for the present disclosure in embodiments thereof. Further, throughout this application, various publications, patents, and published patent applications are referred to by an identifying citation. The disclosures of the publications, patents, and published patent applications referenced in this application are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains.